The invention relates to an arrangement for open-end rotor spinning having a spinning rotor which is supported at a rotor shaft which is disposed in wedge-shaped gaps formed by pairs of supporting disks. The rotor shaft is driven by means of a tangential belt which is loaded in the direction toward the rotor shaft by means of a pressure roller arranged on a movable arm loaded by a spring. This pressure roller is capable of being moved away from the tangential belt for interrupting the drive of the spinning rotor.
Arrangements of the initially mentioned type, as known, for example, from DE-A-34 24 511, are used very successfully in open-end rotor spinning because they permit very high rotational speeds of the rotor.
An object of the invention is to develop an arrangement of the initially mentioned type such that the running properties are improved.
This object is achieved according to the invention by assigning a cleaning element to the peripheral area of the pressure roller.
The invention is based on the recognition that, in practice, difficulties may arise because of the fact that the peripheral area of the pressure roller which is in contact with the tangential belt may pick up dirt deposits. These deposits may be of such an extent that the pressure rollers can no longer run quietly and smoothly. As a result, operating noises are increased, on the one hand, while, on the other hand, the bearings of the supporting disks as well as the bearing of the pressure roller are stressed more extensively. These problems are avoided by means of the cleaning element.
In a further development of preferred embodiments of the invention, it is provided that the cleaning element is constructed as a friction element. This results in a very simple structural design which requires only relatively low expenditures.
In a further development of preferred embodiments of the invention, it is provided that, between the cleaning element and the pressure roller, a space is left which can be bridged by moving the pressure roller and/or the cleaning element. In this development, the pressure roller and the cleaning element are not in constant contact. They are brought in contact with one another only at intervals, for example, at regular intervals or whenever there is a yarn breakage and the drive of the spinning rotor is interrupted anyhow.
In certain preferred embodiments of the invention, it is provided that the cleaning element is held by means of a holding device in the moving path of the pressure roller, along which path the pressure roller moves when moving away from the tangential belt. As a result, it is ensured that a cleaning of the pressure roller takes place during each interruption of the drive.
In a further development of preferred embodiments of the invention, it is provided that the pressure roller is equipped with collars which, when the drive is interrupted, move against the shaft of the spinning rotor. Thus, the collars take over the radial securing of the shaft of the spinning rotor as soon as the radial position securing which in the normal operation is carried out by the tangential belt is largely discontinued.
In a further development of preferred embodiments of the invention, it is provided that the collars are constructed as friction linings. As a result, it becomes possible to brake the rotor shaft via the pressure roller or its collars in such a manner that additional braking elements are not required. In order to keep the masses that have to be braked small, it is provided in a further development of the invention that the collars are rotatably mounted with respect to the pressure roller and their own braking elements are assigned to them. When the pressure roller, via the collars, takes over the function of the rotor shaft brake, the space in the axial direction of the rotor shaft between the supporting disks may be relatively small so that, as a result, a reduction of the axial length of the rotor shaft is obtained. As a result, extremely high rotational speeds may be obtained without any passing through the critical rotational speed for the spinning rotor.
In a further development of preferred embodiments of the invention, it is provided that the cleaning element is held and can be applied to the pressure roller by means of a movable holding device. In an expedient development, it is provided in this case that the cleaning element is constructed as a lift-off device for the pressure roller. In this case, during the stoppage, the lift-off roller is lifted off by means of the cleaning element so that, in this case also, a cleaning process is automatically associated with any stoppage.
Particularly, when the cleaning element can be applied to the pressure roller according to certain preferred embodiments, it is possible to clean the pressure roller in selectable intervals without interrupting the drive for this purpose. In this case, it is possible that the application of the cleaning element to the pressure roller is triggered by means of an automatic servicing apparatus which patrols along a spinning machine which is equipped with a plurality of spinning devices or units of this type.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjuction with the accompanying drawings.